A limitation of our framework is that it only applies to the case of weighted graphs with nonnegative weights, that is \(\mathbf {W}=\lbrace w_{ij}\rbrace _{1\le i,j\le N} \in \mathbb {R}_{+}^{N\times N}\) . Other approaches exist for the case of directed graphs with positive and negative weights but they are not compatible with the one presented here [1]}, [2]}, [3]}.
